A significant improvement in the areal density of conventional magnetic recording media such as hard disks has been achieved by, for example, reducing the size of magnetic particles constituting a recording layer, changing materials, and improving the precision of head processing. Further improvements in areal density are also expected in the future. The improvements in areal density by means of conventional improvement techniques are approaching their limit, however, due to the advent of problems such as processing limits with respect to the magnetic heads, erroneous recording of information on tracks adjoining an intended track ascribable to a spreading recording field, and crosstalk during reproduction.
Discrete track media and patterned media have been proposed as promising magnetic recording media that are capable of providing a further improvement in areal density. In these media, a recording layer is formed in a concavo-convex pattern including the convex portions of the concavo-convex pattern that serve as recording elements (for example, see Patent Literature 1). Meanwhile, for magnetic recording media such as hard disks, the surface flatness is a significant factor in stabilizing the head flying height in order to provide favorable recording and reproducing characteristics. It is therefore desirable to deposit a filler material over the recording layer formed in a concavo-convex pattern so as to fill the concave portions between the recording elements with the filler material, and remove an excess of the filler material over the recording layer so that the recording elements and the filler material are flattened at the top. The filler material may be oxides which are nonmagnetic and chemically stable (for example, see Patent Literature 2). The filler material may be deposited to fill the concave portions by using sputtering or other techniques. In order to remove any excess filler material and thereby provide surface flattening, techniques such as chemical mechanical polishing (CMP) or dry etching can be used.